Ratings for what was once the most unbeatable juggernaut in television, American Idol, have fallen precipitously over the last several years, and that is due in part to cannibalization from other singing competitions. I don’t watch the three big singing competitions — though ratings for all three are still very strong — and to be honest, with all the names that are constantly being bandied about with concern to who is judging what show, I’ve gotten completely confused. In the grand scheme of things, it’s not that important to me, really. But at the very least, when a judge is being roundly mocked or criticized on the Internets, it’s nice to know which show she he or she belongs to. More importantly, whenever strangers hear that I write about television, they always ask me about these singing competitions, and feel weird explaining that I don’t write about THAT kind of television. I write about Breaking Bad and Community, which is always met with quizzical looks.

So, for my own edification, here’s a brief Guide to Who Judges What Show.

American Idol — Still the leader of the crowd, “Idol” attempts to shake things up after each year of ratings erosion. Since last season, the Ryan-Seacrest hosted show has shed both Jennifer Lopez and Steven Tyler, both of whom had short stints show following the departures of Simon Cowell, Paula Abdul, Kara DioGuardi and — at one point — Ellen Degeneres. There’s only one original judge remaining, Randy Jackson, and according to reports this morning, that’s still an open question. Who do we KNOW will be returning in January?

Mariah Carey is the only CONFIRMED judge for next season. With Jackson potentially on the outs (and according to some reports, returning only in a mentor capacity), there are two more slots yet to be filled. Reports have emerged that Nicki Minaj will also be joining the competition, but that has not been confirmed. Other celebrities that are apparently the frontrunners are country singer Keith Urban and Latin singer-songwriter Enrique Iglesias, although I believe that Kanye West was once a possibility, as was Alanis Morisette.

The Voice — The third season of The Voice actually premieres tonight, and from what I understand, there’s been no turnover. The singing competition was kind of the first to sign top-name talent who were still somewhat currently relevant (as opposed to the likes of Paul Abdul and J Lo), and those four judges remain: Cee Lo Green, Adam Levine, Blake Shelton, and Christina Aguilera. I could not tell you, however, a single contestant who has ever won or been on the show.

The X-Factor — The newest entry — which returns Wednesday night — comes from Simon Cowell, and while its first season was one of the ten most profitable shows on television, there was nevertheless a sense of urgency to shake up the judges table after mediocre ratings. After one season, Nicole Sherzinger, Cheryl Cole, and former Idol judge, Paula Abdul, were all sh*tcanned. The only returning judges are Simon Cowell and L.A. Reid, although I have no idea who that is.